1. Field of the Invention
This invention relates to a throw-away insert wherein cutting edges and their sides associated with the rake surface are improved.
2. Description of the Prior Art
FIG. 1 is a top view of an example of a conventional throw-away insert as disclosed, e.g., in U.S. Pat. No. 3,383,748, having a groove of given cross-section formed along all cutting edges, with a land 1 of given width interposed therebetween.
In the throw-away insert shown in FIG. 1, the cross-sectional shape is constant along the cutting edges. Thus, in certain types of cutting, such as profile cutting, where the depth of the cut varies, there has been a problem because satisfactory disposal of chips is impossible. Accordingly, the use of the throw-away insert in an unmanned machining tool has encountered difficulties.
FIG. 2 is a top view of another example of a throw-away insert which has heretofore been used in profile cutting as disclosed, e.g., in Japanese utility model publication No. 33924/1982 (unexamined) showing an insert having raised portions 3 disposed at suitable locations on the rake surface.
The throw-away insert shown in FIG. 2, unlike the one shown in FIG. 1, has its cross-sectional shape varied along the cutting edges. Therefore, under various cutting condition, disposal of chips can be smoothly effected. However, when the insert is clamped to a tool holder, the support surfaces, indicated hatching in FIG. 2, are small, and hence, in profile cutting where the depth of the cut varies, there has been a problem that the insert is liable to break.